Sifting or screening mechanism.



R. A. CUMMINGS. ISIFTING 0R SCREENiNG MECHANISM.

APPLICATION mm SEPT. 9, 1915.

I 1,207,139. Patented Dec. 5, 1916.

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R. A. CUMMINGS.

SIFTING 0R SCREENING MECHANISM.

APPLICATION FILED SEPT. 9, l9l5. 1,207,139. Patented Dec. 0, .1916.

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ROBERT A. CUMMINGS, OF PITTSBURGH, PENNSYLVANIA.

SIFTING' OR SCREENING MECHANISM.

Specification of Letters Patent.

Patented Dec. 5, 1916.

Application filed September 9, 1915. Serial No. 49,745.

To all whom it may concern.

Be it known that I, ROBERT A. CUMMINGS, a resident of Pittsburgh, in thecounty of Allegheny and State of Pennsylvania, have invented a new anduseful Improvement in Sifting or Screening Mechanism, of which thefollowing is a specification.

This invention relates to apparatus for grading or classifying granularor finely divided solid material, such as sand, gravel, clay or thelike, and by means of which the material can be very accuratelyclassified or divided into grades of different sizes or othercharacteristics.

The object of the invention is to provide for grading or classifying anygranular or finely divided solid material, whether the grains are coarseor of very minute size, or both, and whereby the material is positivelyseparated and accurately divided or classified into uniform grades.

Heretofore the practice has been to grade or classify sand, gravel,clay, and other granular or finely divided material by means of a seriesof substantially horizontal screens of progressively finer meshdownwardly, and upon the upper one of which the raw, unclassifiedmaterial is supplied, and which screens are agitated or shaken laterallyto cause the finer grades of material to pass through the severalscreens in succession, each screen throwing off material of a gradecorresponding to its openings. In such prior apparatus gravity has beenthe only force for causing the finer material to pass through thescreens and it has been found necessary to agitate the screensconstantly and quite violently in order to cause the particles to passthrough them, and as the result of such agitation a considerable amountof a finer grade is carried over the edge of each screen along with thecoarser grade which it is the purpose of that particular screen toseparate-out. As a result the separation or classification is notaccurate. Furthermore, some materials are so finely divided or thegrains are of such The present invention provides for a progressiveseparation or classification of any kind of finely divided or granularmaterial, whether containing coarse or very minute grains, or both, intobatches or grades of accurately uniform sizes, the grading orclassification of the coarse and very fine sizes being effected atthesame time in a single apparatus by forcing the material by centrifugalaction, either dry or wet, in succession through one or-a plurality ofscreens of increasing fineness of mesh, for grading the coarser sizes,and if grains of very mi- 'clry material or finely divided material insuspension in a liquid without any flow of said liquid and purely by theaction of centrifugal force.

A further object of the invention is to provide such a construction ofseparating chambers or cylinders containing the classifying screens thatthey may be either filled with liquid or supplied with a current ofliquid so as to keep the material in suspension-and thereby secure amore rapid operation and prevent clog ing of the screens.

A further object of-the invention is to pro-' vide apparatus soconstructed that the material being screened or sifted may be given alateral movement across the screens, as well as a movement directlythrough said screens, so as to insure all of the finer particlestraveling through each of the successive screens and prevent the finergrades being retained along with the coarser grades collected upon anyparticular screen.

Further objects of the invention are in part obvious and in part willappear more in detail hereinafter.

In the drawings, which illustrate a suitableform of mechanism embodyingthe invention, Figure 1 is'a side elevation, partly in sect ion on theline 1 -1, Fig. 2, the dotted lines indicating the elevated position ofthe cylinder; Fig. 2 is a plan view of the rotatable frame and the partscarried thereby;

Fig. 3 is a sectional elevation on the line- 83, Fig. 1, showing thedriving mechanism; Fig. 4. is a detail longitudinal section, on a largerscale, showing one of the separating screens; Fig. 5 is a cross sectionon the line 55. Fig. 1; Fig. 6 is a detail cross section on the line 66,Fig. 2: Fig. 7 is a detail view. corresponding to Fig. 1, and showing adifferent position of the valve member in the elutriator: and Fig. 8 isa detail view, showing a modification.

The essential parts of the apparatus illustrated comprise a frame 1secured to a vertical rotatable shaft 2 and adapted to be whirled aroundby said shaft, and one or more separating chambers or cylinders 3mounted in said whirling frame and normally lying in horizontalposition, together with suitable means for rotating the shaft 2 in orderto whirl the frame 1 and produce a centrifugal action in the separatingchambers or cylinders 3.

As illustrated in the drawings, the machine is supported upon a suitablebase 4,I I, I I I I eration and to produce a further grading or fromwhich rises an upright frame 5 "in which the vertical rotatable shaft 2is journaled. The machine may be .p0wer'"driven,

and for this purpose may be 'connectedito j any suitable driving device,such as an elec' f. tric mo tor, for example by a belt from saidmoto'rpa sing overa pulley 6 on the driving I I end of the'chamber; andwhich screens have 1 their edge's clamped between annular mem bers 21and 22 threaded to each other. The

shaft 2. The particular machine shown may also be operated by hand, andfor this purpose is provided with a horizontal shaft 7 II journaled atits outer end in a bearing 8 and provided with an operating handle 9.The opposite end of the shaft 7 is journaled in the f ame 5 and isprovided with a gear 10 meshing with a pinion 11 on a countershaft 12journaled in a hinged frame 13 which swings about a shaft 14 as an axis,

said shaft 14 lying parallel with the shaft On the countershaft 12 is aspiral toothed wheel 15 engaging with a worm 16 on the shaft 2. thelatter of which has its upper end squared and fitting a similarly shapedopening in a cross member 17 located at the middle of the frame 1. Thehinged frame 13 enables the hand driving mechanism to be site an openingin the frame 5 in which is an adjustable pressure screw 19 which can beforced into engagement with the arm 18 to press the gears 11 and 15 intocooperating engagement with their companion gears 10 and .16.

By means of either the power driving. pulley 6 or the hand drivingmechanism de high speed and the frame 1 carried by said shaft is rapidlywhirled around so as to produce the centrifugal action in the separatingdevices, as will more fully hereinafter appear.

Two or more separating chambers may be tion through the screens from theend of the I separting' chamber located. nearest the shaft 2 to itsopposite end.

The separating chambers may be variously constructed, but preferablywill be so arranged that the material to be classified can not escapetherefrom without passing through the screens, and preferably also insuch a manner that a constantly flowing stream of liquid may be passedthrough said screens in order to' assist'the classifying opclassifyingoperation in the elutriator, as

will more fully appear, I I

Asfspecifi'cally shown in Fig. 1,the separating icylinderlis"providedwith a series of transversescreens" 2Q 'wlnch are successively of finermesh fronrthe mne'r'to the outer annular member 22' on each screen nestswithin the annular-,member 21 of the next adjacent screen, so that theseries of annular members for the several screens form practically 'acontinuous cylindrical shell. The

outermost ring 22 nests within a plain ring I 23 abutting afunnel-shaped pan 24:, forming the outer end of the separating chamber,and the innermost of the annular members ,21 has fitted thereagainst acap 25, said cap and the pan 24 being connected by a cylindrical sheetmetal drum or casing 26, whose inner surface closely fits a series ofoutwardly extending projections 28 on the annular members 21 and 22 forspacing the screens centrally in their casing. One of said rings, suchas the ring 23, may be provided with a small hole or holes 23 permittingthe liquid to flow in between the rings and their casing 26 to preventleakage, if desired.

The material to be graded or classified is placed in the chamber 30between the cap mem er 25 and the first'sc'reen 20, and after theclassification by forcing the material by centrifugal action through theseveral.

I I I I screens in series. the" coarsest gradeofma scribed-the'verticalshaft 2 can :be'-r0tated'-at-* terial will remain in' sa'id chamber 30While the material in the chambers between successive screens will be ofsuccessively finer and finer grades, with the finest material in thechamber 31 between the last of the screens and the outer pan 24. Thematerial may be screened in dry condition, or if desired, the entireseparating cylinder may be filled with liquid, such as water, in whichthe material is held in suspension so that it more readily passesthrough the successive screens. The fine material collected in thechamber 31 may be subjected to a further grading or classifyingoperation so as to separate it into other grades. For this purpose anelutriator is attached to the outer end of the chamber 3 and so arrangedthat communication between the chamber 3 and the elutriator may beeither. closed to dispense with the elutriator in classifying drymaterial or when said elutriator, for other reasons, is not required, ormay be established so that both classifying devices operatesimultaneously.

The elutriator comprises an inner member 32 whose inner end is threadedupon the outer end of the pan 2 1 and is provided with several outwardlyextending radial wings or projections 33, and whose outer portion isprovided with a plurality, three being shown, of annular concentricwalls 3 1 which lie within the annular chambers Or spaces 35 between theannular concentric walls 36 of'an outer member 37. The walls and 36 forma tortuous passage through the elutriator, conducting the liquid and thematerial held in suspension therein successively through the threechambers The walls are so proportioned in thickness and relative spacingthat the several chambers 35 in turn are of increasing cross sectionalarea, so that the stream of liquid flowing t-herethrough has a graduallydecreasing velocity, as will be readily understood. The outer member 37of the elutriator is threaded into a cap 38 whose inner reduced end isconnected to the outer end of a shell or casing 39 surrounding thecylinder 3,'and of larger size than said c linder so as to form anannular passage 40 between the outer shell and cylinder 3. The wings orprojections 33 on the inner member 32 of the elutriator fit within theinner wall of the cap 38 and hold the cylinder 3 and inner member of theelutriator in central position in the outer shell or casing. Thecylinder 3 is also held securely against longitudinal movement in thecasing 39 by clamp screws 39, which also force the caps and rings of theinner shell 3 into close interlocking or nesting engagement with eachother.

The inner end of the chamber 30 within the cap 25 communicates with apassage ll in a member 42 attached to the cross member 17 of the frame1, saidpassage at its opposite end communicating with a vertical-relocity of flow of pipe 4-3 whose axis coincides with the axis of theshaft 2 around which the frame 1 revolves. This enables the material insuspension in a liquid, or clear liquid, to be introduced to the chamber3 through a substantially stationary conduit, which may be easilyconnected to a supply conduit by a swivel joint. The annular passage 40between the inner and outer casings communicates at its inner end withan annular passage ill in the member 42, which passage in turncommunicates with an upwardly extending pipe or conduit 45 whose upperend has a lateral extension or bend 4L6 lying within a container orreceptacle 47 carried by and rotatable with the pipe 43, said receptaclebeing open at its upper end, as at 4:8, and having a downwardlyextending discharge pipe 19 whose lower end travels around in astationary receiver 50 carried by the frame 5, said receiver having asuitable discharge pipe 51. lVith this arrangement the dry material maybe placed in the chamber 30 and sub'ected to the action of a current ofliquid introduced through the pipe .3, or the material may be mixed withthe liquid in a suitablelixiviator, and introduced directly into theapparatus in suspension in a current of liquid. The stream of liquidpasses through the separating chamber 3, forcing the material in turnthrough the successive separating screens 20. each of which collects aparticular grade of a size which will not pass through said screen. Thefiner material passes to the chamber 31 and thence into and through thetortuous passages of the elutriator. On the inner side of each of thewalls 34 is a passage 52 through which the material and liquid passoutwardly, so that the flow is assisted by centrifugal force. On theouter side of each of said walls is a passage 53, and in said passagesthe liquid and material travel inwardly. In these passages the flow ofthe material. with the current is opposed by centrifugal force, whichtends to throw the particles of material. outwardly. This produces theWell known grading action which separates the material into grades ofdecreasing size, the coarser grade being deposited or collected in theinner chamber 35 and the finer grades successively in the outerchambers. The clear liquid remaining after the last separation in theouter chamber 35 travels inwardly through the annular passage 10, thenthrough the passage 4::l: and through pipe 45 into the receptacle 47,from which it passes downwardly through the pipe it) to the outlet fromthe receiver 50.

The grades of material. deposited in the several chambers 35 depend insize upon the the liquid passing through said chambers, since eachchamber collects material of such a size or Weight that the centrifugalforce tending to throw such material outwardly is greater than the forceof the current tending'to carry the material inwardly. The pipe 415leading into the receptacle 47 is rotatable in its supports about itsown axis, so that the outlet from said pipe through the lateral bend 46canbe placed at difierent distances from the axis of the shaft 2, asindicated by the dotted lines in Fig.2. The velocity of flow :of thestream of liquid through the entire apparatus depends upon the distanceof the outlet from this pipe 45 from the axis of the shaft 2,whichdistance determines the head produced by centrifugal force.Consequently, by adjusting said pipe to different positions the velocityof flow of the liquid through the entire apparatus can be varied so'as'to var the grades deposited in the various chambers 35. Each chamber35 is provided at its outer end with an outlet through which thematerial deposited therein may be removed. As shown, the outer member 37of the elutriator is provided with an opening into each of saidchambers, said openings being closed by tapered pins 54 held in place bywinged nuts 55.

For closing communication between the separating chamber 3 andelutriatorthe inner e'n'd' of the member 32 is'provided with 30*" avalve seat 56 for cooperation with a valve member '57 carried on theinner endof a tube 58 threaded into" the outer end of the" member3.7.'In its "outer-position, as shown in 1, when the chamber 3 and elutriator"are in communication with each other, the

valve member 57 is seated' against the inner end of' the inner annularwall 36' of the outer member 37, but by screwing the tube 58 inwardly tothe position shown in Fig. 7 communication between the chamber 3 andelutriatoris wholly shut off; Within the tube 58 is a solid rod 59 whoseouter end is threaded into a guide '60 and is provided withalongitudinal passage 61 opening-at one end through the outer end of therod and at its inner end communicating through a port 62 with an annularspace 63between the'rod 59 and tube 58. The inner end of said rod worksin an opening through the valve member 57 and is provided'with a head 64normally sealing said opening and with a longitudinal slot 65 behindsaid head.

This rod normally occupies the position shown in Fig. 1, so that theopening through the valve 57is closedby the head 64, and no material'canpass outwardly through said valve. The rod may be adjusted inwardly,however, to the position shown in Fig. 7, in which position materialcollected in the chamber 31 may pass outwardly through the slot 65 tothe passage 63 and thence'outwardly through port 62 and "passage '61.This device is'used for cleaningv the apparatus'or for removing agradecollected: or depositedin 'the 'ch'amber' 31? a.

from said chamber so as to take out the grades deposited therein.Inasmuch as the centrifugal force produces a severe outward thrust ofthe chamber 3 and elutriator, suitable antifriction means is providedfor the bearing in the ring 66, such as the ballbearings shown at 68.Ballbearings are also I provided at the inner end of the chamber 3, theouter member of said bearing being threaded internally to receive alongitudinally adjustable ring 71carried by the mem ber 12. This member71 can be disconnected from the member 70, by screwing it to theposition shown in dotted lines, Fig. 1, which disconnects the chamber 3from the member 42 and enables it to be lifted to the position shown indotted lines for inserting a new charge.

When two separating chambers or cylinders are used both thereof willcommunicate with the same feed pipe 43, and said chambers or cylinderswill be'mounted on opposite sides of the axis of rotation ofthe shaft 2,so that they balance each other. In the drawings, only a single cylinderis shown, said cylinder being counterbalanced by a suitablecounterweight 75, which is clamped between the two nuts 76 adjustablelongitudinally upon a threaded shaft 77 carried by cross members 78 ofthe frame 1. This porting shaft in order to accurately counterbalancethe separating cylinder.

In addition to the whirling motion to which the separating cylinder issubjected,

said cylinder is also preferably given a ro-' tary motion aboutits ownaxis, so as to change the position of the screens relatively to thematerial passing therethrough and produce a centrifugal action on saidmaterial radial to the axis of the cylinder 3, to assist in forcing thematerial through the screens. This rotary movement can be effected byvarious means and may be either an intermittent or a continuous rotarymovement. As shown in Fig. l, a suitable abutment 80 is secured to theframe 5 with its upper end in position to be contacted by the peripheryof the cylinder 39 as it moves over the same. This abutment can be madeof some friction material, such as leather or the like to cotiperatewith the smooth surface of the cylinder 39, and'produces a gentle butregular intermittent rotation of the cylinder. Various other means maybe applied for givingsaidfrotarymotion, such 3 I gal force.

as providing the periphery of the cylinder with ratchet notches or teethand substitut ing a pawl for the abutment member 80. If a continuousrotary movement is desired the cylinder may be provided with gear teeth81, as shown in Fig. 8, which mesh with a horizontal annular rack 82mounted on the frame 5 concentric with the shaft 2, or, some of theteeth of the rack 82 may be omitted at intervals, so as to produce anintermittent rotation of the cylinder.

lVhenever the cylinder is rotated upon its axis the material beingforced through the screens is gently shifted laterally across thescreens and clogging of the screens is prevented and a more readypassage of the material through the screens is effected. The separatingcylinder may also be moved or vibrated transversely about its axis toassist in distributing or moving the particles transversely of theseparating screens. One suitable construction for producing this resultconsists in providing one or a plurality of small knobs or cams 83 uponthe frame 5 just below the lower end of the member 17, which is slidablevertically upon the upper squared end of the shaft 2 and is providedwith a depending projection 84: which travels over and engagessuccessively the knobs 83, each engagement producing a slight lift ofthe frame 1 and all of the parts carried thereby. The result is ajarring or vibration of the separating cylinder which is of materialassistance in securing the passage of the particles through the screens.This device may be used alone or in combination with suitable means suchas that described for rotating the receptacle about its own axis.

In the apparatus described the material does not escape from the edgesof the screens and by the action of centrifugal force the finerparticles are forced through the several screens screens in succession.Each screen holds back only such particles as are too large to passthrough it, and the positive action of the centrifugal force insuresthat all particles of a smaller size will be passed through thatparticular screen. Consequently the material is separted or classifiedinto grades of uniform size, and there is no danger of a coarser gradecontaining a portion of the finer material, as with existing screeningmethods. The result is that the classification is much more accurate andsharply defined than in existing methods. \Vhen the material to beclassified contains particles of very minute size, such particles can befurther accurately graded or classified in the elutriator by the actionof a current or stream of liquid opposed by centrifu- The centrifugalforce acts to force the particles very rapidly through the elutriator,as a result of which a batch of unclassified material can be separatedvery rapidly into definite grades.

What I claim is:

1. Apparatus for classifying solid materials comprising a rotatablymounted frame, a receptacle mounted on said frame, and an inner shell insaid receptacle containing a plurality of screens of varying mesh whoseplanes are parallel to the axis of rotation of said frame.

2. Apparatus for classifying solid materials comprising a rotatablymounted frame, a receptacle mounted on said frame, and a plurality ofscreen members so mounted in said frame as to form an inner shelltherein with a passage surrounding said members.

3. Apparatus for classifying solid materials comprising a rotatablymounted f 'ame, a. receptacle mounted on said frame, and a plurality ofscreens of varying mesh having interlocking peripheral portions formingan inner shell in said receptacle and spaced from said receptacle toform a passage surrounding said screens.

at. Apparatus for classifying solid materials comprising a rotatablymounted frame, a. receptacle mounted thereon, a removable cap on saidreceptacle, and a plurality of screens of varying mesh havinginterlocking peripheral portions held together by said cap to form aninner shell in said receptacle.

5. Apparatus for classifying solid materials comprising a rotatablymounted frame, a receptacle mounted thereon, a removable cap on saidreceptacle, and a plurality of screens in said receptacle with theirplanes parallel to the axis of rotation of said frame, the screennearest said cap being of the coarsest mesh and each succeeding screenbeing of finer mesh than the preceding screen.

6. Apparatus for classifying solid materials comprising a rotatablymounted frame, a receptacle mounted thereon, a re movable cap on saidreceptacle, a plurality of screens in said receptacle with their planesparallel to the axis of rotation of said frame, the screen nearest saidcap being of the coarsest mesh and each succeeding screen in order beingof finer mesh than the preceding screen, interlocking peripheralportions on said screens, and means for forcing said portions intomutual interlocking engagement.

7. Apparatus for classifying solid materials comprising a rotatablymounted frame, a receptacle journaled on said frame, an inner shellcontaining a plurality of screens of varying mesh in said receptacle,means for rotating said frame, and means for rotating said receptaclerelatively thereto.

8. Apparatus for classifying solid materials comprising a rotatablymounted frame, a receptacle journaled on said frame, a plurality ofscreen members so mounted in said frame as to form an inner and meansfor rotating said receptacle relaframe,

shell therein, means forrotating said frame,

and means forrotating said receptacle rela- ;t1vely. thereto.

.locking peripheral portions held together by said cap to form an innershell in said receptacle, means for rotating said frame,

tively thereto.

11. Apparatus for classifying solid materials comprising a rotatablymounted frame, a receptacle journaled therein, a removable cap on saidreceptacle, a plurality of screens in said receptacle, the screennearest sald cap being of the coarsest mesh and each succeeding screenin order being of finer mesh than the preceding screen, means forrotating said frame, and means for rotating said receptacle relativelythereto.

12. Apparatus for classifying solid materials comprising a rotatablymounted frame, a receptacle journaled therein, a removable cap on saidreceptacle, a plurality of, screens in said receptacle, the screennearest said cap being of the coarsest mesh and each succeeding screenbeing of finer mesh than the preceding screen, interlocking peripheralportions on said screens, means for forcing said portions into mutualinterlocking engagement, means for rotating said frame, and means .forrotating said receptacle relatively thereto.

13. Apparatus for classifying solid materials comprising a rotatablymounted frame, a receptacle journaled on said frame, an .inner shellcontaining a plurality of screens of varying mesh insaid receptacle,means for rotating said frame, and means for rotating said receptaclerelatively thereto and for jarring the same.

14. Apparatus for classifying solid materials comprising a rotatablymounted frame, a receptacle journaled on said frame, a. plurality ofscreen members so mounted in said frame as to form an inner shelltherein, means for rotating said frame, and means for rotating saidreceptacle relatively thereto and for jarring the same.

15. Apparatus for classifying solid materials comprising a rotatablymounted frame, a receptacle journaled in said frame,

16. Apparatus for classifyingsolicl materails comprising a rotatablymounted frame, a receptacle journaled therein, a removable cap on said.receptacle, a plurality of screens of varying mesh having interlockingperipheral portions held together by said cap to form an inner. shell insaid receptacle,

means for rotating said frame, andmeans for rotating said receptaclerelatively thereto and for jarringthe same.

17. Apparatus for classifyingsolid .materials comprisinga rotatablymounted frame, a receptacle journaled therein, a removable cap on saidreceptacle, a plurality of screens in said receptacle, the screennearest said cap being of thecoarsest mesh and each succeeding screen inorder being of finer mesh than the preceding screen, means for rotatingsaid frame, and means for. rotating said receptacle relatively theretoand for jarring the same.

18. Apparatus for classifyingsolidmaterials comprising a rotatablymounted receptacle, a screen Within said receptacle having its surfacein a plane parallelto the axis of rotation, and ,means for conductingliquid through said screen.

19. Apparatus for classifying solid materials, comprising a rotatably.mounted Treceptacle, a plurality of screens of varying mesh therein andhaving theirsurfaces in planes parallel to the axis of rotation, andmeans for conducting liquid succe'ssii' 'ely through said screens.

20. Apparatus for classifying solid materials, comprising a rotatablymounted frame, a receptacle thereon containing a plurality of screens ofvarying mesh With their surfaces in planes parallelto the axis ofrotation, and means for circulating liquid through said screens.

21. Apparatus for classifying [solid .1na-- terials, comprising arotatably mounted frame, a receptacle ournaled on.said frame,

a plurality of screens of varying mesh in said receptacle Whose surfacesare in planes parallel to the axis of rotatiomand means for circulatingliquid successively through said screens.

22. Apparatus forclassifying solid mate rials, comprising av rotatablymounted frame, a receptacle on said frame, an inner shell containing aplurality of screens of varying mesh in said receptacle, and a casingsurrounding said receptacle and forming a passage communicating with thespace Within said receptacle.

23. Apparatus forclassifying solid materials, comprising a rotatably.mounted frame, a receptacle on said frame, an inner shell containing aplurality of screens of varying mesh in said receptacle, a casingsurrounding said receptacle and forming a passage communicating with thespace with in said receptacle, and means for supplying a stream ofliquid to said receptacle.

24. Apparatus for classifying solid materials, comprising a rotatablymounted frame, a receptacle journaled on said f 'ame, an inner shellcontaining a plurality of screens of varying mesh in said receptacle,

and a casing surrounding said receptacle and forming a passagecommunicating with the space within said receptacle.

25. Apparatus for classifying solid materials, comprising a rotatablymounted frame, a receptacle journaled on said frame, an inner shellcontaining a plurality of screens of varying mesh in said receptacle, acasing surrounding said receptacle and forming a passage communicatingwith the space within said receptacle, and means for rotating saidreceptacle.

26. Apparatus for classifying solid materials, comprising a rotatablymounted frame, a receptacle containing a screen pivotally mounted insaid frame, and means for conducting liquidthrough said receptacle.

27. Apparatus for classifying solid materials, comprising a rotatablymounted frame, a receptacle pivotally mounted in said frame on an axistransverse to the axis of rotation of said frame and containing ascreen, said receptacle being also rotatable about an axis perpendicularto said first named axes, and means for conducting liquid through saidreceptacle.

28. Apparatus for classifying solid materials, comprising a rotatablymounted frame, a receptacle pivotally mounted in said frame on an axistransverse to the axis of rotation of said frame and containing ascreen, said receptacle being also rotatable about an axis perpendicularto said first named axes. means for conducting liquid through saidreceptacle, and means for rotating said receptacle in its frame.

29. Apparatus for classifying solid materials, comprising a. frame, areceptacle therein containing a screen and communicating with a seriesof chambers of different areas of cross section, andmeans for conductingliquid through said screen and chambers.

30. Apparatus for classifying solid materials, comprising a receptaclecontaining a screen, an elutriator communicating with said receptacle,and means for closing communication between said receptacle and elutriator.

31. Apparatus for classifying solid ma terials, comprising a rotatablymounted frame, a receptacle journaled therein and containing a screen,an elutriator communicating with said receptacle, and means forconducting liquid through said receptacle and elutriator.

32. Apparatus for classifying solid materials, comprising a rotatablymounted frame, a receptacle carried by said frame and containing aplurality of screens of varying mesh, a casing surrounding saidreceptacle and forming a passage therebetween, and an elutriatorconnected to said casing and communicating with said passage and withthe space within said receptacle.

33. Apparatus for classifying solid materials, comprising a rotatablymounted frame, a receptacle carried by said frame and containing aplurality of screens of varying mesh, a casing surrounding saidreceptacle and forming a passage therebetween, an elutriator connectedto said casing and communicating with said passage and with the spacewithin said receptacle, and means for closing communication between saidreceptacle and elutriator.

34:. Apparatus for classifying solid materials comprising a rotatablymounted frame, a receptacle mounted on said frame at one side of theaxis of rotation and adapted to be whirled around by the same, and aplurality of screens of varying mesh mounted in said receptacle withtheir planes parallel to the axis of rotation of said frame.

35. Apparatus for classifying solid materials comprising a rotatablymounted frame, a receptacle journaled on said frame and containing aplurality of screens of varying mesh with their planes parallel to theaxis of rotation of said frame, means for rotating said frame, and meansfor rotating said receptacle in said frame.

36. Apparatus for classifying solid materials, comprising a rotatablymounted frame, a receptacle journaled on said frame, a plurality ofscreens mounted in said frame with their planes parallel to the axis ofrotation of said frame, means for rotating said frame, means forrotating said receptacle in said frame, and means for jarring saidreceptacle.

In testimony whereof, I have hereunto set my hand.

ROBERT A. CUMMINGS.

Witnesses:

GLENN H. ZERESOHE, C. B. SANDERSON.

Copies of this patent may be obtained for five cents each, by addressingthe Commissioner of Patents, Washington, D. 0.

